System and method for dynamically configuring a target device

ABSTRACT

In accordance with the present disclosure, a method for dynamically configuring a target device comprises receiving by one or more ports of a target device one or more initiator identifiers from one or more initiators. The method further comprises determining whether a plurality of ports received initiator identifiers from a common initiator. The method further comprises configuring the plurality of the ports to operate as a single, logical port if the plurality of ports received initiator identifiers from a common initiator.

TECHNICAL FIELD

The present disclosure relates generally to information handling systemsand specifically to a system and method for dynamically configuring atarget device.

BACKGROUND

As the value and use of information continues to increase, individualsand businesses seek additional ways to process and store information.One option available to users is information handling systems. Aninformation handling system generally processes, compiles, stores,and/or communicates information or data for business, personal, or otherpurposes thereby allowing users to take advantage of the value of theinformation. Because technology and information handling needs andrequirements vary between different users or applications, informationhandling systems may also vary regarding what information is handled,how the information is handled, how much information is processed,stored, or communicated, and how quickly and efficiently the informationmay be processed, stored, or communicated. The variations in informationhandling systems allow for information handling systems to be general orconfigured for a specific user or specific use such as financialtransaction processing, airline reservations, enterprise data storage,or global communications. In addition, information handling systems mayinclude a variety of hardware and software components that may beconfigured to process, store, and communicate information and mayinclude one or more computer systems, data storage systems, andnetworking systems.

Information handling systems often use storage resources to store data.Storage resources may store data on one or more logical storage units,also known simply as “logical units.” Each logical unit may be made upof one or more hard disk drives, magnetic tape libraries, optical diskdrives, magneto-optical disk drives, compact disk drives, compact diskarrays, disk array controllers, and/or any other type ofcomputer-readable media. The storage resources may be included in SerialAttached Small Computer System Interface (Serial Attached SCSI or (SAS))component target devices that are communicatively coupled to one or moreinitiating devices. The initiating devices may send information to orrequest information from the target devices. As the rate at which thetarget devices may retrieve and store data increases, the rate ofinformation transfer between target and initiating devices may need tobe increased to fully take advantage of the rapid storage and retrievalrates.

SUMMARY

In accordance with the present disclosure, a method for dynamicallyconfiguring a target device comprises receiving by one or more ports ofa target device one or more initiator identifiers from one or moreinitiators. The method further comprises determining whether a pluralityof ports received initiator identifiers from a common initiator. Themethod further comprises configuring the plurality of the ports tooperate as a single, logical port if the plurality of ports receivedinitiator identifiers from a common initiator.

In accordance with another embodiment of the present disclosure aninformation handling system configured to dynamically configure a targetdevice comprises one or more ports communicatively coupled to one ormore initiators. The ports are configured to receive initiatoridentifiers from the one or more initiators. The system furthercomprises a control unit communicatively coupled to the one or moreports. The control unit is configured to determine whether a pluralityof ports have received initiator identifiers from a common initiator.The control unit is further configured to configure the plurality ofports to operate as a single, logical port if the plurality of portseach received an initiator identifier from a common initiator.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsfeatures and advantages, reference is now made to the followingdescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 illustrates an example system for dynamically configuring aSerial Attached Small Computer System Interface (Serial Attached SCSI or(SAS)) target device;

FIG. 2 illustrates another example system for dynamically configuring aSAS target device;

FIG. 3 illustrates another example system for dynamically configuring aSAS target device;

FIG. 4 illustrates another example system for dynamically configuring aSAS target device; and

FIG. 5 illustrates an example method for dynamically configuring a SAStarget device.

DETAILED DESCRIPTION

Preferred embodiments and their advantages are best understood byreference to FIGS. 1-5, wherein like numbers are used to indicate likeand corresponding parts.

For the purposes of this disclosure, an information handling system mayinclude any instrumentality or aggregate of instrumentalities operableto compute, classify, process, transmit, receive, retrieve, originate,switch, store, display, manifest, detect, record, reproduce, handle, orutilize any form of information, intelligence, or data for business,scientific, control, entertainment, or other purposes. For example, aninformation handling system may be a personal computer, a PDA, aconsumer electronic device, a network storage device, or any othersuitable device and may vary in size, shape, performance, functionality,and price. The information handling system may include memory, one ormore processing resources such as a central processing unit (CPU) orhardware or software control logic. Additional components or theinformation handling system may include one or more storage devices, oneor more communications ports for communicating with external devices aswell as various input and output (I/O) devices, such as a keyboard, amouse, and a video display. The information handling system may alsoinclude one or more buses operable to transmit communication between thevarious hardware components.

For the purposes of this disclosure, computer-readable media may includeany instrumentality or aggregation of instrumentalities that may retaindata and/or instructions for a period of time. Computer-readable mediamay include, without limitation, storage media such as a direct accessstorage device (e.g., a hard disk drive or floppy disk), a sequentialaccess storage device (e.g., a tape disk drive), compact disk, CD-ROM,DVD, random access memory (RAM), read-only memory (ROM), electricallyerasable programmable read-only memory (EEPROM), and/or flash memory; aswell as communications media such as wires, optical fibers, microwaves,radio waves, and other electromagnetic and/or optical carriers; and/orany combination of the foregoing.

An information handling system may include or may be coupled via anetwork to one or more arrays of storage resources. The array of storageresources may include a plurality of storage resources, and may beoperable to perform one or more input and/or output storage operations,and/or may be structured to provide redundancy. In operation, one ormore storage resources disposed in an array of storage resources maylogically appear to an operating system as a single logical unit.

FIG. 1 illustrates an example system 100 for dynamically configuring aSerial Attached Small Computer System Interface (Serial Attached SCSI or(SAS)) target device. System 100 may include one or more initiators 102,one or more targets 104, and one or more communication media 112. In thepresent example, one initiator 102 and one target 104 are depicted, butthe present disclosure should not be limited to such. Initiator 102 mayinclude one or more processors 106, one or more memories 108 and one ormore physical ports 110. Target 104 may include one or more physicalports 114, one or more control units 116 and one or more storage devices118.

Initiator 102 may be communicatively coupled to target 104 via ports 110and 114, and via communication media 112. Although system 100 depicts adirect connection between initiator 102 and target 104 via communicationmedia 112, the present disclosure should not be limited to such.Initiator 102 and target 104 may be connected via a network thatincludes none, one or more nodes between initiator 102 and target 104.Accordingly, communication media 112 may comprise any suitablecommunication media that may be included in a network, such as wires,optical fibers, microwaves, radio waves, and other electromagneticand/or optical carriers; and/or any combination of the foregoing.

Initiator 102 may be an information handling system configured toinitiate a SCSI session between initiator 102 and one or more targets104. SCSI is a set of standards for physically connecting andtransferring data between information handling systems. The SCSIstandards define commands, protocols, and electrical and opticalinterfaces. Initiator 102 may initiate a SCSI session with target 104 bysending a SCSI command to target 104. For example, one type of SCSIcommand may comprise a command to retrieve data from, or send data totarget 104.

Initiator 102 may include a processor 106 configured to perform theoperations of initiator 102, such as initiate SCSI sessions with target104. Processor 106 may include any system, device, or apparatus operableto interpret and/or execute program instructions and/or process data,and may include without limitation a microprocessor, microcontroller,digital signal processor (DSP), application specific integrated circuit(ASIC), or any other digital or analog circuitry configured to interpretand/or execute program instructions and/or process data. In someembodiments, processor 106 may interpret and/or execute programinstructions and/or process data stored in an associated memory 108and/or another component of an associated initiator 102.

Memory 108 may be communicatively coupled to its associated processor106 and may comprise any system, device or apparatus operable to retainprogram instructions or data for a period of time (e.g.,computer-readable media). In the present disclosure, memory 108 mayinclude instructions for initiating and creating a SCSI session that maybe read and executed by processor 106. Memory 108 may include randomaccess memory (RAM), electrically erasable programmable read-only memory(EEPROM), a PCMCIA card, flash memory, magnetic storage, opto-magneticstorage, or any suitable selection and/or array of volatile ornon-volatile memory that retains data after power to its initiator 102is turned off.

Initiator 102 may also include one or more physical ports 110. Althoughthe present disclosure depicts initiator 102 including two ports 110,initiator 102 may include more or fewer ports 110. Ports 110 may becommunicatively coupled to processor 106 and/or memory 108 and may beconfigured to interface initiator 102 with transmission media forcommunicating with other devices such as target 104. Examples of ports110 may comprise wireless transmitters/receivers, opticaltransmitters/receivers, Ethernet ports, etc. Ports 110 may sometimes bereferred to as “Phys.” Multiple physical ports 110 may be groupedtogether and act as a single logical port. Target 104 may also includephysical ports 114, which may be similar or identical to physical ports110. As mentioned above, initiator 102 and target 104 may becommunicatively coupled to each other via ports 110 and 114, andtransmission media 112.

Target 104 may comprise any system, apparatus, or device configured tostore data. Target 104 may include one or more storage devices 118configured to store data. Storage devices 118 may comprise logicalstorage units (“LUNs”) which may comprise one or more hard disk drives,magnetic tape libraries, optical disk drives, magneto-optical diskdrives, compact disk drives, compact disk arrays, disk arraycontrollers, solid state storage devices (“SSdevices” or “SSDs”) thatcomprise flash memory, and/or any other type of computer-readable media.Storage device 118 may also be configured to retrieve data to be used bytarget 104 or initiator 102. Storage device 118 may also store datareceived by target 104 from initiator 102.

Target 104 may include physical ports 114 similar to physical ports 110.Target 104 may be configured to receive SCSI commands from initiator 102at ports 114 and to perform functions according to those commands. Forexample, target 104 may receive a SCSI data retrieval request frominitiator 102 and target 104 may retrieve that data from storage device118 to be sent to initiator 102. In another example, target 104 mayreceive a data storage command from initiator 102, wherein initiator 102directs target 104 to store data on storage device 118.

In traditional embodiments, the ports of a target device may beconfigured to operate either in “wide mode” or “narrow mode” beforebeing coupled to an initiator. In such embodiments, the ports of thetarget device may not change from either “narrow mode” or “wide mode”once they have been set to that particular mode.

Operating in “narrow mode” may generally refer to each physical port ofa target device acting as a separate independent port or interfacebetween a target and initiator. While operating in narrow mode, thebandwidth, or rate of data transmission, between a target and initiator,may be limited to the bandwidth of each individual port.

Operating in “wide mode” may refer to a plurality of ports groupedtogether to act as a single logical port. While operating in wide mode,the bandwidth of the logical port may be the aggregate of the bandwidthof each individual port. Consequently, the data transmission rate of theports operating in “wide mode” to act as a single logical port may behigher than a single port acting as one, individual port, in “narrowmode.”

As the rate of data storage/retrieval of storage devices included intargets 104 increases, the need to operate in “wide mode” increases. Byoperating in “wide mode” devices (e.g., initiators 102 and targets 104)may take advantage of the high speed storage device capabilities becausethe bandwidth of a single port may not be capable of supporting the datastorage and retrieval speeds of these high speed storage devices.

Unlike traditional embodiments, physical ports 114 of target 104 may bedynamically configured to operate in “narrow mode” or “wide mode” uponconnection to one or more initiators 102. Therefore, target 104 may beconfigured to determine if its physical ports 114 should operate innarrow mode or wide mode, depending on the application, and mayconfigure itself accordingly.

Target 104 may include control unit 116 configured to determine whetherports 114 of target 104 should operate in “narrow mode” or “wide mode.”Control unit 116 may include a processor and memory, similar toprocessor 106 and memory 108 included in initiator 102, to store andperform the operations of control unit 116. Additionally, althoughtarget 104 is depicted as including only one control unit 116, thepresent disclosure should not be limited to such. For example, adifferent control unit 116 may correspond with each port 114, to performand control the operations with respect to that individual port 114.

Control unit 116 may determine whether ports 114 a and 114 b of target104 should operate in narrow or wide mode according to whether the sameinitiator 102 is coupled to more than one port 114. In the presentexample, initiator 102 is coupled to target 104 via port 110 a,transmission media 112 a and port 114 a. Initiator 102 is also coupledto target 104 via port 110 b, transmission media 110 b, and port 114 b.Accordingly, a single initiator (initiator 102) is coupled to more thanone port 114 (ports 114 a and 114 b) of target 104 in the presentexample. Thus, control unit 116 may determine that ports 114 a and 114 bof target 104 should operate in wide mode, such that physical ports 114a and 114 b are considered as one logical port, with respect toinitiator 102.

Control unit 116 may determine that initiator 102 is coupled to bothports 114 a and 114 b upon initialization and booting of target 104after target 104 has been coupled to initiator 102. When target 104 ispowered on, ports 114 a and 114 b may receive an initialization requestfrom initiator 102 to synchronize ports 110 a and 110 b with ports 114 aand 114 b respectively. Initiator 102 may send an initiator identifierin each initialization request that identifies initiator 102 as theinitiator sending the request. Control unit 116 may compare theinitiator identifier received at port 114 a with the initiatoridentifier received at port 114 b. Because both initiator identifiersoriginated from initiator 102, the two initiator identifiers may be thesame. Accordingly, control unit 116 may determine that both ports 114 aand 114 b are coupled to initiator 102, and that ports 114 a and 114 bshould operate in wide mode.

Upon determining that ports 114 a and 114 b should operate in wide mode,control unit 116 may configure ports 114 a and 114 b accordingly. Uponreceiving an initialization request from initiator 102 at port 114 a,control unit 116 may send a port identifier to initiator 102 identifyingport 114 a via port 114 a, transmission medium 112 a and port 110 a.After determining that target 104 should operate in wide mode, controlunit 116 may also send the port identifier associated with port 114 a toinitiator 102 via port 114 b, transmission medium 112 b and port 110 b.Accordingly, initiator 102 may “see” both ports 114 a and 114 b as onelogical port having a single port identifier.

In alternative embodiments, the port identifier associated with port 114b may be used instead of the identifier associated with port 114 a. Itmay be irrelevant which identifier is used as long as a singleidentifier is sent to initiator 102 for every port 114 coupled to thesame initiator 102. Additionally, although target 104 is depicted asbeing coupled to initiator 102 via two ports 112, the present disclosureshould not be limited to such.

In some embodiments, control unit 116 may delay the initialization ofport 114 b until port 114 a has been initialized, or vice versa. Forexample, both ports 114 a and 114 b may receive initialization requestsfrom initiator 102, but port 114 b may not begin configuration untilafter port 114 a has been configured. Control unit 116 may indicate thatport 114 a has been configured by setting a bit indicating so. With thatbit set, control unit 116 may be configured to begin configuration ofport 114 b. Once port 114 a has been configured, control unit 116 maybegin configuration of port 114 b by first comparing the initiatoridentifiers received by ports 114 a and 114 b. Thus, control unit 116may determine whether ports 114 a and 114 b are coupled to the sameinitiator.

In other embodiments, ports 114 a and 114 b may each include controlunits that may control configuration of their respective ports. In suchembodiments, the control unit associated with port 114 a may beconfigured to set the bit indicating that port 114 a has beenconfigured, and the control unit associated with port 114 b may beconfigured to read the bit to determine whether or not to beginconfiguration of port 114 b.

In yet other embodiments, control unit 116 may set a bit indicating thatport 114 a has received an initialization request even before port 114 ais completely configured, and control unit 116 may compare the initiatoridentifiers received at port 114 a and 114 b upon that bit being set.Accordingly, control unit 116 may also begin configuration of port 114 bupon that bit being set, once port 114 b has received an initializationrequest.

It may be advantageous to wait for port 114 a to be configured or towait until port 114 a receives a initialization request beforeconfiguring port 114 b because initiator 102 may send the initializationrequests at different times. Accordingly, if port 114 b were to receivean initialization request before port 114 a, waiting to configure port114 b before configuring port 114 a may prevent control unit 116 fromattempting to compare the initiator identifier received at port 114 bwith an initiator identifier received at port 114 a before port 114 aeven receives an initiator identifier. Thus, control unit 116 may beprevented from falsely determining that ports 114 a and 114 b are notboth coupled to the same initiator 102 solely because port 114 a has notyet received an identifier for comparison.

Although, the present example depicts port 114 b waiting until port 114a is configured, port 114 a may wait until port 114 b is configuredinstead of port 114 b waiting until port 114 a is configured withoutdeparting from the scope of the disclosure. In embodiments that mayinclude more than two ports 114, any appropriate prioritizing scheme maybe utilized to determine the order in which ports 114 may be configured.

Modifications, additions or omissions may be made to system 100 withoutdeparting from the scope of the disclosure. For example, system 100 mayinclude more initiators 102 and more targets 104 than those depicted.Additionally, initiator 102 and target 104 may include more ports thanthe number depicted, and also may include other components that performsome, more or none of the operations described.

FIG. 2 illustrates another example system 200 for dynamicallyconfiguring a SAS target device. System 200 is similar to system 100except it depicts two initiators 102 coupled to target 104. In system200, initiator 102 a is coupled to target 104 via port 110 a,transmission medium 112 a and port 114 a. Additionally, initiator 102 bis also coupled to target 104 via port 110 c, transmission medium 112 b,and port 114 b.

Upon powering up, target 104 may receive an initialization request frominitiator 102 a via port 114 a and an initialization request frominitiator 102 b via port 114 b. The initialization request frominitiator 102 a may include an initiator identifier associated withinitiator 102 a, and the initialization request from initiator 102 b mayinclude a different initiation identifier associated with initiator 102b.

Once the initialization request is received at port 114 a, control unit116 may begin configuration of port 114 a. Once the initializationrequest is received at port 114 b, control unit 116 may wait until port114 a has received its initialization request or has finishedconfiguration similar to that described with respect to FIG. 1.

Upon configuration of port 114 a, control unit 116 may compare theinitiator identifier received at port 114 a with the initiatoridentifier received at port 114 b. Because the initiator identifiers arefrom different initiators 102, the initiator identifiers may bedifferent. Accordingly, control unit 116 may determine that port 114 ais coupled to a different initiator than port 114 b, and that ports 114a and 114 b of target 104 should operate in narrow mode.

Control unit 116 may configure ports 114 a and 114 b of target 104 tooperate in narrow mode. In the present example, control unit 116 mayhave already sent initiator 102 a a port identifier associated with port114 a, via port 114 a, just as described with respect to FIG. 1 whentarget 104 was configured to operate in wide mode. Accordingly, port 114a may be configured such that the port identifier associated with port114 a may be sent to the initiator coupled to port 114 a regardless ofwhether port 114 a is operating in narrow or wide mode. Thus, theconfiguration of port 114 a in either narrow or wide mode may be similaror identical.

However, unlike in wide mode of port 114 b where control unit 116 maysend a port identifier associated with port 114 a via port 114 b to makeit logically appear that ports 114 a and 114 b are the same port, innarrow mode, control unit 116 may send a port identifier associated withport 114 b via port 114 b to initiator 102 b. Accordingly both ports 114a and 114 b may act as logically separate, independent ports due toports 114 a and 114 b being coupled to initiators 102 a and 102 brespectively.

Modifications, additions, or omissions may be made to system 200 withoutdeparting from the scope of the disclosure. For example, although port114 a is depicted as being configured first, port 114 b may beconfigured before port 114 a in other embodiments. Additionally, thenumber of ports shown is for illustrative purposes, and the presentdisclosure should not be limited to such.

FIG. 3 illustrates another example system 300 for dynamicallyconfiguring a SAS target device. System 300 is substantially similar tosystem 100 except that initiator 102 is depicted as only being coupledto target 104 via port 110 b, transmission medium 112 b and port 114 b.In this particular example, upon receiving an initialization request atport 114 b, control unit 116 may set a timer for port 114 b. While thetimer is running, control unit 116 may continue to check to see if theflag or bit is set that indicates that port 114 a is configured. If thebit is set before the timer expires—which may occur in instances whereport 114 a is coupled to an initiator, such as described with respect toFIGS. 1 and 2—control unit 116 may proceed with the configuration ofport 114 b in either wide or narrow mode similar to that described withrespect to FIGS. 1 and 2.

However, if the timer expires before port 114 a is configured, controlunit 116 may determine that port 114 a is not coupled to initiator 102,and may configure port 114 b to operate in narrow mode by sending theport identifier associated with port 114 b to initiator 102.Accordingly, if only port 114 b is coupled to initiator 102, such asshown in system 300, control unit 116 may configure port 114 b withoutport 114 a being configured. Otherwise, in a situation such as thatdepicted in FIG. 3, if control unit 116 were to wait for port 114 a tobe configured before configuring port 114 b, port 114 b may never beconfigured.

Additionally, although the description with respect to FIGS. 1 and 2describes control unit 116 waiting to configure port 114 a until port114 b is configured, the timer may be used with respect to systems 100and 200 also. With respect to systems 100 and 200, the timer may alsoallow for configuration of port 114 b after expiration of the timer toprevent indefinitely waiting to configure port 114 b if port 114 a isexperiencing some sort of failure or problem that is preventing port 114a from being configured.

The timer may be set to correspond with the delay time for configurationof a port based on the SAS standard. The timer may also be set toaccount for time discrepancies between receipt of initializationrequests at different ports. Once this delay has passed control unit 116may reasonably ascertain that port 114 a is not coupled to an initiator102, or is experiencing a failure or problem.

Modifications, additions or omissions may be made to system 300 withoutdeparting from the scope of the disclosure. For example, although thetimer is described as being associated with the SCSI delay time, thepresent disclosure is not limited to such. Additionally, although thetimer has been described with respect to port 114 b, the timer may beassociated with port 114 a instead of port 114 b if port 114 b is to beconfigured first. The labeling of specific ports is for descriptivepurposes only.

FIG. 4 illustrates an example system 400 also configured to dynamicallyconfigure a SAS target device. System 400 is similar to systems 100-300depicted in FIGS. 1-3, but depicts two initiators 102, initiators 102 aand 102 b, and target 104 is depicted as including four ports 114, ports114 a, 114 b, 114 c and 114 d.

Ports 114 may be prioritized according to a prioritization scheme. Forexample port 114 a may have the highest priority, port 114 b may havesecond priority, port 114 c may have third priority and port 114 d mayhave fourth and last priority.

Control unit 116 may determine if any of the ports 114 are coupled tothe same initiator 102. For any group of ports coupled to the sameinitiator, control unit 116 may configure the ports to logically appearto the shared initiator as a single port. Control unit 116 may configurethe ports 114 that are coupled to the same initiator 102 to logicallyappear as a single port by sending the same port identifier through allthe ports coupled to the shared initiator. In some instances, the sameport identifier may be associated with the highest prioritized portcoupled to the shared initiator, as described below.

In the present example, port 114 a may receive an initialization requestfrom initiator 102 a via port 110 a and transmission medium 112 a. Port114 b may also receive an initialization request from initiator 102 avia port 110 b and transmission medium 112 b. Both initializationrequests from initiator 102 a may include identical initiatoridentifiers because both requests originated from initiator 102 a.Additionally, ports 114 c and 114 d may each respectively receiveinitialization requests from initiator 102 b via ports 110 c and 110 d,and transmission media 112 c and 112 d. The initialization requestsreceived from initiator 102 b may each also include identical initiatoridentifiers that identify initiator 102 b.

Control unit 116 may sequentially configure port 114 a first, port 114 bsecond, port 114 c third and port 114 d fourth and last according to theprioritization scheme. For example, upon receipt of an initializationrequest at port 114 a, control unit 116 may begin configuration of port114 a, which may include sending a port identifier associated with port114 a through port 114 a to initiator 102 a. Due to port 114 a havingthe highest priority, in the present example, regardless of whether port114 a is coupled to the same initiator as another port 114, control unit116 may send a port identifier associated with port 114 a through port114 a to the initiator coupled to port 114 a.

Upon receipt of an initialization request at port 114 b, control unit116 may delay configuration of port 114 b until port 114 a has beenconfigured. Upon receipt of an initialization request at port 114 c,control unit 116 may delay configuration of port 114 c until both ports114 a and 114 b have been configured, and upon receipt of aninitialization request at port 114 d, control unit 116 may delayconfiguration of port 114 d until ports 114 a, 114 b and 114 c have allbeen configured.

After port 114 a has been configured, because ports 114 a and 114 b arecoupled to the same initiator in the present example, control unit 116may configure port 114 b to operate in wide mode with respect to port114 a, similar to that described with respect to FIG. 1. In alternativeembodiments where ports 114 a and 114 b are not coupled to the sameinitiator 102, control unit 116 may configure port 114 b similar to thatdescribed with respect to FIG. 2. In yet other embodiments, port 114 bmay be associated with a delay timer to contemplate situations when port114 a is not coupled to an initiator or is disabled. In situations whereport 114 a is disabled or not coupled to an initiator, control unit 116may configure port 114 b similar to that described with respect to FIG.3.

Even though the descriptions of FIGS. 1-3 specifically relate to systemswith targets 104 that have only two ports, while system 400 in FIG. 4relates to a target 104 that has four ports, the configuration of port114 b may be the same with respect to FIG. 4 because port 114 b may bethe second prioritized port. Due to the prioritization in the presentexample, configuration of port 114 b may depend only on whether port 114b is coupled to the same initiator 102 as port 114 a. If ports 114 b and114 a are coupled to the same initiator 102, port 114 a's portidentifier may be sent through port 114 b such that ports 114 a and 114b logically appear and act as a single port with respect to the sharedinitiator 102. However, if ports 114 b and 114 a are not coupled to thesame initiator 102, with port 114 b being second priority, the portidentifier associated with port 114 b may be sent through port 114 b,regardless of whether the lower priority ports are coupled to the sameinitiator as port 114 b. Therefore, in the present example, port 114 b'sconfiguration may depend only on whether or not it is connected the sameinitiator 102 as port 114 a (e.g., operating in wide mode with port 114a), regardless of whether or not port 114 b is operating in narrow orwide mode with respect to the other ports 114.

Returning to FIG. 4, after ports 114 a and 114 b have been configured,control unit 116 may begin configuration of port 114 c. In configurationof port 114 c, control unit 116 may first compare the initiatoridentifier received at port 114 c with the initiator identifier receivedat port 114 a. In the present example, the initiator identifiers may notbe equal, because the initialization request received at port 114 aoriginated from initiator 102 a, whereas the initialization requestreceived at port 114 c originated from initiator 102 b. Therefore,control unit 116 may determine that ports 114 a and 114 c are notcoupled to the same initiator and may then determine whether ports 114 band 114 c are coupled to the same initiator.

Control unit 116 may compare the initiator identifiers received at ports114 b and 114 c and may determine that ports 114 b and 114 c also arenot coupled to the same initiator. Accordingly, after determining thatport 114 c is not coupled to the same initiator as any of the ports withhigher priority than port 114 c (e.g., ports 114 a and 114 b), controlunit 116 may send a port identifier associated with port 114 c throughport 114 c to initiator 102 b during configuration of port 114 c. Asdescribed with respect to ports 114 a and 114 b, in the present exampledue to the prioritization, configuration of port 114 c may only dependon whether it is coupled to the same initiator as any of the ports 114that have higher priority (e.g., ports 114 a and 114 b), but not thosethat have lower priority (e.g., port 114 d).

In another embodiment, ports 114 a and 114 c may be coupled to the sameinitiator. In such an embodiment, due to port 114 a having highestpriority, control unit 116 may configure port 114 c by sending a portidentifier associated with port 114 a through port 114 c. Control unit116 may forgo checking whether or not ports 114 c and 114 b are coupledto the same initiator because, due to the prioritization scheme, even ifport 114 b is coupled to the same initiator as port 114 c (and thus alsocoupled to the same initiator as port 114 a) control unit 116 may sendthe port identifier associated with port 114 a through each of ports 114a, 114 b, and 114 c to the initiator coupled to all the ports, such thatthe initiator 102 “sees” the three ports as one single logical port. Insuch a scenario where ports 114 a and 114 c are coupled to the sameinitiator 102, due to the higher prioritization of port 114 a,determining whether ports 114 b and 114 c are also coupled to the sameinitiator 102 may be irrelevant because regardless of whether ports 114b and 114 c are coupled to the same initiator 102, control unit 116 maysend a port identifier associated with port 114 a through port 114 c.

In yet another embodiment, ports 114 b and 114 c may be coupled to thesame initiator 102, but may be coupled to a different initiator 102 thanport 114 a. In such a scenario, after determining that port 114 c is notcoupled to the same initiator 102 as port 114 a and then afterdetermining that port 114 c is coupled to the same initiator 102 as port114 b, control unit 116 may send a port identifier associated with port114 b through port 114 c to the initiator 102 shared by ports 114 b and114 c. Control unit 116 may send the port identifier associated withport 114 b through port 114 c because port 114 b may have a higherpriority than port 114 c.

Additionally, in embodiments that utilize a delay timer for port 114 b,a delay timer may also be associated with port 114 c. Like a timerassociated with port 114 b, upon receipt of an initialization request atport 114 c, control unit 116 may start the timer associated with port114 c.

The timer associated with port 114 c may be longer than the timerassociated with port 114 b. Due to the prioritization of port 114 c withrespect to port 114 b, the timer may need to be long enough to allow forconfiguration of both ports 114 a and 114 b, and if port 114 b has adelay timer also, the delay for port 114 c may need to account for that.Similarly to the function and purpose of a delay timer described abovewith respect to port 114 b, once the timer with respect to port 114 cexpires, if neither ports 114 a nor 114 b are configured, control unit116 may configure port 114 c and send a port identifier associated withport 114 c through port 114 c. Accordingly, control unit 116 may avoidindefinitely waiting to configure port 114 c if ports 114 a and 114 bare either not coupled to an initiator 102 or are disabled for somereason.

Returning to FIG. 4, after configuration of port 114 c, control unit 116may configure port 114 d. Due to the prioritization, in the presentexample, control unit 116 may first determine that ports 114 d and 114 aare not coupled to the same initiator 102, then determine that ports 114d and 114 b are not coupled to the same initiator 102, and finallydetermine that ports 114 d and 114 c are coupled to the same initiator102 (e.g. initiator 102 b), and that port 114 d should operate in widemode with respect to port 114 c.

Upon determining that ports 114 d and 114 c are coupled to the sameinitiator 102, control unit 116 may send a port identifier associatedwith port 114 c to initiator 102 b through port 114 d duringconfiguration of port 114 d. Therefore, ports 114 c and 114 d maylogically appear as a single port to initiator 102 b. Once again,control unit 116 may send the port identifier associated with port 114 cthrough port 114 d because port 114 c has a higher priority than port114 d. Due to port 114 d being the lowest priority port, in anyembodiment where control unit 116 determines that port 114 d is coupledto the same initiator 102 as any other port 114, control unit 116 maynot send the port identifier associated with port 114 d to the sharedinitiator 102. Accordingly, in the present example, control unit 116 maysend the port identifier associated with port 114 d only in instanceswhere port 114 d is not coupled to the same initiator 102 as any of theother ports of target 104.

In other embodiments, port 114 d may be associated with a delay timersimilar to those that ports 114 c and 114 b may be associated with. Thetimer may be longer than the timer associated with ports 114 b and 114 cdue to the lower prioritization of port 114 d, similarly to why thetimer associated with port 114 c may be longer than the timer associatedwith port 114 b.

Modifications, additions or omissions may be made to system 400 withoutdeparting from the scope of the disclosure. Once again, the number ofinitiators 102 and ports 114 is merely for illustrative purposes and thedisclosure should not be limited to such. Additionally, a particularprioritization scheme has been described with respect to ports and portidentifiers; however, the present disclosure should not be limited tosuch. Any system apparatus or device configured to dynamically configuretargets according to determinations of shared initiators is contemplatedby the present disclosure. For example, the present disclosure describesport identifiers of a particular port being used but other embodimentsmay utilize a port identifier for a group of ports acting as a singleport that is not associated with any of the ports in the group.

FIG. 5 illustrates an example method 500 for dynamically configuring aSAS target device (e.g., target device 104). Method 500 may start atstep 502, where a target device, may receive an initialization requestfrom an initiator. The initialization request may include an initiatoridentifier. In the present example, the target device may be similar totarget 104 depicted in FIG. 1 and may include two ports (ports A and B),similar to ports 110 a and 110 b. Although the present example isdescribed with respect to a target device having only two ports, thedisclosure should not be limited to such. The target device may havemore than two ports, such as target 104 depicted with respect to FIG. 4.

At step 504, the target device may determine whether the initiatoridentifier was received at port A or port B. If the initiator identifierwas received at port A, the target device may proceed to step 506. Ifthe initiator identifier was received at port B, the target device mayproceed to step 510. In some instances, the target device may receive aninitiator identifier at port A and shortly thereafter receive aninitiator identifier at port B or vice versa. Accordingly, although somethe following steps may be described in a sequential order, it isunderstood that the target device may perform the steps of method 500associated with port A while also simultaneously performing some stepsof method 500 associated with port B.

At step 506, the target device may send a port A identifier to theinitiator through port A to configure and identify port A. At step 508,the target device may set a bit or flag to indicate that port A has beenconfigured, and method 500 may end.

At step 510, if an initiator identifier is received at port B instead ofport A, the target device may start a delay timer for port B. At step512, the target device may determine whether the timer has expired. Ifthe timer has not expired, method 500 may proceed to step 514, otherwisemethod 500 may proceed to step 520.

At step 514, the target device may check the bit or flag that indicateswhether port A has been configured to determine if port A has beenconfigured. If port A has not been configured, the target device mayreturn to step 512 to determine whether the delay timer has expired. Ifport A has been configured, the target device may proceed to step 516.

At step 516, the target device may determine whether the initiatoridentifier received at port A is equal to the initiator identifierreceived at port B. If the initiator identifiers are equal, the targetdevice may determine that ports A and B are coupled to the sameinitiator and may proceed to step 518. If the identifiers are not equal,the target device may determine that ports A and B are not coupled tothe same initiator and may proceed to step 520.

At step 518, the target device may send the port A identifier throughport B to the initiator coupled to both ports A and B. Accordingly, dueto the initiator having also received the port A identifier through portA, as described in step 508, the initiator may logically “see” ports Aand B as one single port, such that port A and port B operate in widemode. Following step 518, the method may end.

At step 520, if the initiator identifiers received at ports A and B arenot equal, as described in step 516, the target device may send a port Bidentifier through port B to the initiator that sent the initiatoridentifier to port B. Accordingly, port B may be configured in narrowmode and may operate as a single port independent from port A.Additionally, as described with respect to step 512, if the timer hasexpired before port A has been configured, at step 520, the targetdevice may also send a port B identifier through port B to the initiatorthat sent the initiator identifier to port B. Therefore, in instanceswhere port A is not coupled to an initiator, is disabled, or does notreceive or process an initiator request for any reason, port B may stillbe configured without having to indefinitely wait for port A to beconfigured, which may never happen. Following step 520, method 500 mayend.

Modifications, additions or omissions may be made to method 500 withoutdeparting from the scope of the disclosure. For example, some steps maybe performed at the same time. Additionally, a target device may havemore than two ports. Also, in other embodiments, the timer may beomitted.

Although the present disclosure and its advantages have been describedin detail, it should be understood that various changes, substitutionsand alterations can be made herein without departing from the spirit andscope of the disclosure as defined by the following claims.

1. A method for dynamically configuring a target device comprising:receiving by one or more ports of a target device one or more initiatoridentifiers from one or more initiators; initiating a delay timer for afirst port of the one or more ports that has received a first initiatoridentifier; detecting whether a second port of the one or more ports hasreceived a second initiator identifier before expiration of the delaytimer; determining whether the first initiator identifier and the secondinitiator identifier were sent by a common initiator, if the second portreceives an initiator identifier before expiration of the delay timer;determining that the second port has not received an initiatoridentifier if the second port has not received an initiator identifierupon expiration of the delay timer; and configuring the plurality of theports to operate as a single logical port if the plurality of portsreceived initiator identifiers from a common initiator.
 2. The method ofclaim 1, further comprising configuring each of the one or more portsthat have not received initiator identifiers from a common initiator asan independent port separate from each of the plurality of ports.
 3. Themethod of claim 2, wherein configuring the one or more ports asindependent ports comprises sending for each of such one or more ports aport identifier, associated with the port, to an initiator from whicheach respective port received an initiator identifier.
 4. The method ofclaim 1, wherein determining whether a plurality of ports received aninitiator identifier from a common initiator further comprises:determining that the initiator identifiers received by at least two ofthe plurality of ports are the same; and determining that the at leasttwo ports received the initiator identifiers from a common initiatorbased on the initiator identifiers being the same.
 5. The method ofclaim 1, wherein determining whether a plurality of ports received aninitiator identifier from a common initiator comprises: determining thatnone of the initiator identifiers received by the plurality of ports arethe same; and determining that none of the plurality of ports receivedthe initiator identifiers from a common initiator based on none of theinitiator identifiers being the same.
 6. The method of claim 1, whereindetermining whether a plurality of ports received an initiatoridentifier from the same initiator comprises: determining that only oneport received an initiator identifier; and determining that none of theports received initiator identifiers from a common initiator based ononly one port receiving an initiator identifier.
 7. The method of claim1, wherein determining whether a plurality of ports received aninitiator identifier from a common initiator comprises delayingconfiguration of a first port that received a first initiator identifieruntil after a second port that has received a second initiatoridentifier has been configured.
 8. The method of claim 1, whereinconfiguring the plurality of the ports to operate as a single, logicalport comprises sending for each of the plurality of ports a portidentifier associated with one port of the plurality of ports to aninitiator common to the plurality of ports.
 9. The method of claim 1,wherein determining whether the first initiator identifier and thesecond initiator identifier were sent by a common initiator comprises:comparing the first initiator identifier with the second initiatoridentifier; determining that the first initiator identifier and thesecond initiator identifier were sent by a common initiator if the firstinitiator identifier and the second initiator identifier are equal; anddetermining that the first initiator identifier and the second initiatoridentifier were sent by different initiators if the first initiatoridentifier and the second initiator identifier are not equal.
 10. Themethod of claim 1, wherein determining whether any of the one or moreports have received an initiator identifier from a common initiatorcomprises: receiving by a first port a first initiator identifier;delaying configuring the first port until after a second port that hasreceived a second initiator identifier has been configured; comparingthe first initiator identifier with the second initiator identifierafter the second port has been configured; determining that the firstinitiator identifier and the second initiator identifier were sent by acommon initiator if the first initiator identifier and the secondinitiator identifier are equal; and determining that the first initiatoridentifier and the second initiator identifier were sent by differentinitiators if the first initiator identifier and the second initiatoridentifier are not equal.
 11. The method of claim 1, wherein the targetdevice comprises a Serial Attached Small Computer System Interface (SAS)target device.
 12. An information handling system configured todynamically configure a target device comprising: one or more portscommunicatively coupled to one or more initiators and configured toreceive initiator identifiers from the one or more initiators; and acontrol unit including a delay timer communicatively coupled to the oneor more ports and configured to: initiate the delay timer for a firstport of the one or more ports that has received a first initiatoridentifier; detect whether a second port of the one or more ports hasreceived a second initiator identifier before expiration of the delaytimer; determine whether the first initiator identifier and the secondinitiator identifier were sent by a common initiator, if the second portreceives an initiator identifier before expiration of the delay timer;and determine that the second port has not received an initiatoridentifier if the second port has not received an initiator identifierupon expiration of the delay timer; and configure the plurality of portsto operate as a single logical port if the plurality of ports eachreceived an initiator identifier from a common initiator.
 13. Theinformation handling system of claim 12, wherein the control unit isfurther configured to configure each of the one or more ports that havereceived an initiator identifier but have not received an initiatoridentifier from a common initiator as an independent port separate fromeach of the other ports.
 14. The information handling system of claim13, wherein the control unit is further configured to direct each portacting as an independent port to send a port identifier, associated withthe port, to an initiator from which each respective port received aninitiator identifier.
 15. The information handling system of claim 12,wherein the control unit is further configured to: determine that theinitiator identifiers received by at least two of the plurality of portsare the same; and determine that the at least two ports received theinitiator identifiers from a common initiator based on the initiatoridentifiers being the same.
 16. The information handling system of claim12, wherein the control unit is further configured to: determine thatnone of the initiator identifiers received by the plurality of ports arethe same; and determine that none of the plurality of ports receivedinitiator identifiers from a common initiator based on none of theinitiator identifiers being the same.
 17. The information handlingsystem of claim 12, wherein the control unit is further configured to:determine that only one port received an initiator identifier; anddetermine that none of the ports received initiator identifiers from acommon initiator based on only one port receiving an initiatoridentifier.
 18. The information handling system of claim 12, wherein thecontrol unit is further configured to direct the plurality of ports thatare to operate as a single logical port to each send a port identifierassociated with one port of the plurality of ports to an initiatorcommon to the plurality of ports.
 19. The information handling system ofclaim 12, wherein the control unit is further configured to: delayconfiguring a first port that has received a first initiator identifieruntil after a second port that has received a second initiatoridentifier has been configured; compare the first initiator identifierwith the second initiator identifier after the second port has beenconfigured; determine that the first initiator identifier and the secondinitiator identifier were sent by a common initiator if the firstinitiator identifier and the second initiator identifier are equal; anddetermine that the first initiator identifier and the second initiatoridentifier were sent by different initiators if the first initiatoridentifier and the second initiator identifier are not equal.
 20. Theinformation handling system of claim 12, wherein the target devicecomprises a Serial Attached Small Computer System Interface (SAS) targetdevice.